    /**
     * @docauthor Jason Johnston <jason@sencha.com>
     *
     * A container for grouping sets of fields, rendered as a HTML `fieldset` element. The {@link #title}
     * config will be rendered as the fieldset's `legend`.
     *
     * While FieldSets commonly contain simple groups of fields, they are general {@link Ext.container.Container Containers}
     * and may therefore contain any type of components in their {@link #cfg-items}, including other nested containers.
     * The default {@link #layout} for the FieldSet's items is `'anchor'`, but it can be configured to use any other
     * layout type.
     *
     * FieldSets may also be collapsed if configured to do so; this can be done in two ways:
     *
     * 1. Set the {@link #collapsible} config to true; this will result in a collapse button being rendered next to
     *    the {@link #title legend title}, or:
     * 2. Set the {@link #checkboxToggle} config to true; this is similar to using {@link #collapsible} but renders
     *    a {@link Ext.form.field.Checkbox checkbox} in place of the toggle button. The fieldset will be expanded when the
     *    checkbox is checked and collapsed when it is unchecked. The checkbox will also be included in the
     *    {@link Ext.form.Basic#submit form submit parameters} using the {@link #checkboxName} as its parameter name.
     *
     * # Example usage
     *
     *     @example
     *     Ext.create('Ext.form.Panel', {
     *         title: 'Simple Form with FieldSets',
     *         labelWidth: 75, // label settings here cascade unless overridden
     *         url: 'save-form.php',
     *         frame: true,
     *         bodyStyle: 'padding:5px 5px 0',
     *         width: 550,
     *         renderTo: Ext.getBody(),
     *         layout: 'column', // arrange fieldsets side by side
     *         defaults: {
     *             bodyPadding: 4
     *         },
     *         items: [{
     *             // Fieldset in Column 1 - collapsible via toggle button
     *             xtype:'fieldset',
     *             columnWidth: 0.5,
     *             title: 'Fieldset 1',
     *             collapsible: true,
     *             defaultType: 'textfield',
     *             defaults: {anchor: '100%'},
     *             layout: 'anchor',
     *             items :[{
     *                 fieldLabel: 'Field 1',
     *                 name: 'field1'
     *             }, {
     *                 fieldLabel: 'Field 2',
     *                 name: 'field2'
     *             }]
     *         }, {
     *             // Fieldset in Column 2 - collapsible via checkbox, collapsed by default, contains a panel
     *             xtype:'fieldset',
     *             title: 'Show Panel', // title or checkboxToggle creates fieldset header
     *             columnWidth: 0.5,
     *             checkboxToggle: true,
     *             collapsed: true, // fieldset initially collapsed
     *             layout:'anchor',
     *             items :[{
     *                 xtype: 'panel',
     *                 anchor: '100%',
     *                 title: 'Panel inside a fieldset',
     *                 frame: true,
     *                 height: 52
     *             }]
     *         }]
     *     });
     */
    Ext.define('Ext.form.FieldSet', {
        extend: 'Ext.container.Container',
        alias: 'widget.fieldset',
        uses: ['Ext.form.field.Checkbox', 'Ext.panel.Tool', 'Ext.layout.container.Anchor', 'Ext.layout.component.FieldSet'],

        /**
         * @cfg {String} title
         * A title to be displayed in the fieldset's legend. May contain HTML markup.
         */

        /**
         * @cfg {Boolean} [checkboxToggle=false]
         * Set to true to render a checkbox into the fieldset frame just in front of the legend to expand/collapse the
         * fieldset when the checkbox is toggled.. This checkbox will be included in form submits using
         * the {@link #checkboxName}.
         */

        /**
         * @cfg {String} checkboxName
         * The name to assign to the fieldset's checkbox if {@link #checkboxToggle} = true
         * (defaults to '[fieldset id]-checkbox').
         */

        /**
         * @cfg {Boolean} [collapsible=false]
         * Set to true to make the fieldset collapsible and have the expand/collapse toggle button automatically rendered
         * into the legend element, false to keep the fieldset statically sized with no collapse button.
         * Another option is to configure {@link #checkboxToggle}. Use the {@link #collapsed} config to collapse the
         * fieldset by default.
         */

        /**
         * @cfg {Boolean} collapsed
         * Set to true to render the fieldset as collapsed by default. If {@link #checkboxToggle} is specified, the checkbox
         * will also be unchecked by default.
         */
        collapsed: false,

        /**
         * @cfg {Boolean} [toggleOnTitleClick=true]
         * Set to true will add a listener to the titleCmp property for the click event which will execute the
         * {@link #toggle} method. This option is only used when the {@link #collapsible} property is set to true.
         */
        toggleOnTitleClick : true,

        /**
         * @property {Ext.Component} legend
         * The component for the fieldset's legend. Will only be defined if the configuration requires a legend to be
         * created, by setting the {@link #title} or {@link #checkboxToggle} options.
         */

        /**
         * @cfg {String} [baseCls='x-fieldset']
         * The base CSS class applied to the fieldset.
         */
        baseCls: Ext.baseCSSPrefix + 'fieldset',

        /**
         * @cfg {String} layout
         * The {@link Ext.container.Container#layout} for the fieldset's immediate child items.
         */
        layout: 'anchor',

        border: 1,

        componentLayout: 'fieldset',

        autoEl: 'fieldset',

        childEls: [
            'body'
        ],

        renderTpl: [
            '{%this.renderLegend(out,values);%}',
            '<div id="{id}-body" class="{baseCls}-body">',
                '{%this.renderContainer(out,values);%}',
            '</div>'
        ],

        stateEvents : [ 'collapse', 'expand' ],

        maskOnDisable: false,

        beforeDestroy: function(){
            var me = this,
                legend = me.legend;

            if (legend) {
                // get rid of the ownerCt since it's not a proper item
                delete legend.ownerCt;
                legend.destroy();
                me.legend = null;
            }
            me.callParent();
        },

        initComponent: function() {
            var me = this,
                baseCls = me.baseCls;

            me.callParent();

            me.addEvents(

                /**
                 * @event beforeexpand
                 * Fires before this FieldSet is expanded. Return false to prevent the expand.
                 * @param {Ext.form.FieldSet} f The FieldSet being expanded.
                 */
                "beforeexpand",

                /**
                 * @event beforecollapse
                 * Fires before this FieldSet is collapsed. Return false to prevent the collapse.
                 * @param {Ext.form.FieldSet} f The FieldSet being collapsed.
                 */
                "beforecollapse",

                /**
                 * @event expand
                 * Fires after this FieldSet has expanded.
                 * @param {Ext.form.FieldSet} f The FieldSet that has been expanded.
                 */
                "expand",

                /**
                 * @event collapse
                 * Fires after this FieldSet has collapsed.
                 * @param {Ext.form.FieldSet} f The FieldSet that has been collapsed.
                 */
                "collapse"
            );

            if (me.collapsed) {
                me.addCls(baseCls + '-collapsed');
                me.collapse();
            }
            if (me.title) {
                me.addCls(baseCls + '-with-title');
            }
            if (me.title || me.checkboxToggle || me.collapsible) {
                me.addCls(baseCls + '-with-legend');
            }
        },

        /**
         * Initialized the renderData to be used when rendering the renderTpl.
         * @return {Object} Object with keys and values that are going to be applied to the renderTpl
         * @private
         */
        initRenderData: function() {
            var data = this.callParent();

            data.baseCls = this.baseCls;

            return data;
        },

        getState: function () {
            var state = this.callParent();

            state = this.addPropertyToState(state, 'collapsed');

            return state;
        },

        afterCollapse: Ext.emptyFn,
        afterExpand: Ext.emptyFn,

        collapsedHorizontal: function () {
            return true;
        },

        collapsedVertical: function () {
            return true;
        },

        createLegendCt: function () {
            var me = this,
                items = [],
                legend = {
                    xtype: 'container',
                    baseCls: this.baseCls + '-header',
                    id: me.id + '-legend',
                    autoEl: 'legend',
                    items: items,
                    ownerCt: me,
                    ownerLayout: me.componentLayout
                };

            // Checkbox
            if (me.checkboxToggle) {
                items.push(me.createCheckboxCmp());
            }
            // Toggle button
            else if (me.collapsible) {
                items.push(me.createToggleCmp());
            }

            // Title
            items.push(me.createTitleCmp());

            return legend;
        },

        /**
         * Creates the legend title component. This is only called internally, but could be overridden in subclasses to
         * customize the title component. If {@link #toggleOnTitleClick} is set to true, a listener for the click event
         * will toggle the collapsed state of the FieldSet.
         * @return Ext.Component
         * @protected
         */
        createTitleCmp: function() {
            var me  = this,
                cfg = {
                    xtype : 'component',
                    html  : me.title,
                    cls   : me.baseCls + '-header-text',
                    id    : me.id + '-legendTitle'
                };

            if (me.collapsible && me.toggleOnTitleClick) {
                cfg.listeners = {
                    el : {
                        scope : me,
                        click : me.toggle
                    }
                };
                cfg.cls += ' ' + me.baseCls + '-header-text-collapsible';
            }

            return (me.titleCmp = Ext.widget(cfg));
        },

        /**
         * @property {Ext.form.field.Checkbox} checkboxCmp
         * Refers to the {@link Ext.form.field.Checkbox} component that is added next to the title in the legend. Only
         * populated if the fieldset is configured with {@link #checkboxToggle}:true.
         */

        /**
         * Creates the checkbox component. This is only called internally, but could be overridden in subclasses to
         * customize the checkbox's configuration or even return an entirely different component type.
         * @return Ext.Component
         * @protected
         */
        createCheckboxCmp: function() {
            var me = this,
                suffix = '-checkbox';

            me.checkboxCmp = Ext.widget({
                xtype: 'checkbox',
                hideEmptyLabel: true,
                name: me.checkboxName || me.id + suffix,
                cls: me.baseCls + '-header' + suffix,
                id: me.id + '-legendChk',
                checked: !me.collapsed,
                listeners: {
                    change: me.onCheckChange,
                    scope: me
                }
            });
            return me.checkboxCmp;
        },

        /**
         * @property {Ext.panel.Tool} toggleCmp
         * Refers to the {@link Ext.panel.Tool} component that is added as the collapse/expand button next to the title in
         * the legend. Only populated if the fieldset is configured with {@link #collapsible}:true.
         */

        /**
         * Creates the toggle button component. This is only called internally, but could be overridden in subclasses to
         * customize the toggle component.
         * @return Ext.Component
         * @protected
         */
        createToggleCmp: function() {
            var me = this;
            me.toggleCmp = Ext.widget({
                xtype: 'tool',
                type: 'toggle',
                handler: me.toggle,
                id: me.id + '-legendToggle',
                scope: me
            });
            return me.toggleCmp;
        },

        doRenderLegend: function (out, renderData) {
            // Careful! This method is bolted on to the renderTpl so all we get for context is
            // the renderData! The "this" pointer is the renderTpl instance!

            var me = renderData.$comp,
                legend, tree;

            // Create the Legend component if needed
            if (me.title || me.checkboxToggle || me.collapsible) {
                me.legend = legend = Ext.widget(me.createLegendCt());

                legend.ownerLayout.configureItem(legend);
                tree = me.legend.getRenderTree();

                Ext.DomHelper.generateMarkup(tree, out);
            }
        },

        finishRender: function () {
            var legend = this.legend;

            this.callParent();

            if (legend) {
                legend.finishRender();
            }
        },

        getCollapsed: function () {
            return this.collapsed ? 'top' : false;
        },

        getCollapsedDockedItems: function () {
            var legend = this.legend;

            return legend ? [ legend ] : [];
        },

        /**
         * Sets the title of this fieldset
         * @param {String} title The new title
         * @return {Ext.form.FieldSet} this
         */
        setTitle: function(title) {
            var me = this,
                legend = me.legend;

            me.title = title;
            if (me.rendered) {
                if (!me.legend) {
                    me.legend = legend = Ext.widget(me.createLegendCt());
                    legend.ownerLayout.configureItem(legend);
                    legend.render(me.el, 0);
                }
                me.titleCmp.update(title);
            }
            return me;
        },

        getTargetEl : function() {
            return this.body || this.frameBody || this.el;
        },

        getContentTarget: function() {
            return this.body;
        },

        /**
         * Expands the fieldset.
         * @return {Ext.form.FieldSet} this
         */
        expand : function(){
            return this.setExpanded(true);
        },

        /**
         * Collapses the fieldset.
         * @return {Ext.form.FieldSet} this
         */
        collapse : function() {
            return this.setExpanded(false);
        },

        /**
         * @private Collapse or expand the fieldset
         */
        setExpanded: function(expanded) {
            var me = this,
                checkboxCmp = me.checkboxCmp,
                operation = expanded ? 'expand' : 'collapse';

            if (!me.rendered || me.fireEvent('before' + operation, me) !== false) {
                expanded = !!expanded;

                if (checkboxCmp) {
                    checkboxCmp.setValue(expanded);
                }

                if (expanded) {
                    me.removeCls(me.baseCls + '-collapsed');
                } else {
                    me.addCls(me.baseCls + '-collapsed');
                }
                me.collapsed = !expanded;
                if (me.rendered) {
                    me.updateLayout();
                    me.fireEvent(operation, me);
                }
            }
            return me;
        },

        getRefItems: function(deep) {
            var refItems = this.callParent(arguments),
                legend = this.legend;

            // Prepend legend items to ensure correct order
            if (legend) {
                refItems.unshift(legend);
                if (deep) {
                    refItems.unshift.apply(refItems, legend.getRefItems(true));
                }
            }
            return refItems;
        },

        /**
         * Toggle the fieldset's collapsed state to the opposite of what it is currently
         */
        toggle: function() {
            this.setExpanded(!!this.collapsed);
        },

        /**
         * @private
         * Handle changes in the checkbox checked state
         */
        onCheckChange: function(cmp, checked) {
            this.setExpanded(checked);
        },

        setupRenderTpl: function (renderTpl) {
            this.callParent(arguments);

            renderTpl.renderLegend = this.doRenderLegend;
        }
    });